Patent Number: 7,132,375

Title: Method of manufacturing a semiconductor device by crystallization of a semiconductor region by use of a continuous wave laser beam through the substrate

Abstract: A technique is provided for forming a crystalline semiconductor film whose orientation is uniform by control of crystal orientation and obtaining a crystalline semiconductor film in which concentration of an impurity is reduced. A configuration of the invention is that a first semiconductor region is formed on a substrate having transparent characteristics of a visible light region, a barrier film is formed over the first semiconductor region, a heat retaining film covering a top and side surfaces of the first semiconductor region is formed over the barrier film, the first semiconductor region is crystallized by scanning a continuous wave laser beam from one edge of the first semiconductor region to the other through the substrate, then the heat retaining film and the barrier film are removed and a second semiconductor region is formed as an active layer of TFT by etching the crystallized first semiconductor region. A pattern of the second semiconductor region formed by etching is formed in a manner that a scanning direction of the laser beam and a channel length direction of the TFT are arranged in almost the same direction in order to smooth drift of carriers.

Inventors: Yamazaki; Shunpei (Tokyo, JP)

Assignee: Semiconductor Energy Laboratory Co., Ltd.

International Classification: H01L 21/26 (20060101); H01L 21/324 (20060101); H01L 21/42 (20060101); H01L 21/477 (20060101)

Expiration Date: 2019-11-07 0:00:00